Apparatus mounted on vehicles for detecting road surface conditions

Abstract

A road surface is scanned with a laser beam in a direction transverse to the road surface to pick up the scanning locus of the laser beam on the road surface in a direction inclined to a beam scanning surface so as to obtain transverse profile data. The laser light reflected from the road surface is received in a direction inclined to the beam scanning surface for obtaining crack data. The distances to the road at three points in the longitudinal direction of a measuring car are measured. The running distance of the car is measured and the measured distance data are recorded in a recording device together with crack data, transverse profile data and longitudinal profile data.

What is claimed is: 
     
       1. A road surface condition detecting apparatus mounted on a vehicle comprising; laser beam scanning means for scanning a laser beam in a transverse direction of the road surface;   image pick-up means for picking up locus of a scanning of said laser beam in an inclined direction for producing transverse profile data of the road surface;   light receiving means for receiving a laser beam reflected from said road surface in an inclined direction for producing crack data of said road surface;   road distance detecting means for measuring distances to said road surface from three positions on a line in the longitudinal direction of said vehicle for producing longitudinal profile data of said road surface;   running distance detecting means for measuring a running distance of said vehicle; and   recording means for recording data respectively produced by said image pick-up means, said light receiving means and said distance detecting means together with the running distance data produced by said running distance detecting means.   
     
     
       2. The apparatus according to claim 1 wherein said laser beam scanning means comprises a rotatable polygonal mirror and a laser beam projector for projecting the laser beam upon said polygonal mirror. 
     
     
       3. The apparatus according to claim 1 wherein said laser beam scanning means has a scanning speed of 2880 times per second. 
     
     
       4. The apparatus according to claim 1 wherein said image pick-up means comprises a first television camera picking up one half of the scanning locus of said laser beam, and a second television camera picking up the other half of said locus. 
     
     
       5. The apparatus according to claim 1 further comprising further light receiving means for receiving reflected light in the direction of projection of said laser beam among light of the laser beam reflected from said road surface, and means for comparing an output of said further light receiving means with an output of said first mentioned light receiving means. 
     
     
       6. The apparatus according to claim 1 wherein said light receiving means comprises a photomultiplier tube. 
     
     
       7. The apparatus according to claim 1 wherein the spacing between said three positions on said longitudinal axis of said vehicle is set to be 1.5 m. 
     
     
       8. The apparatus according to claim 1 wherein said road distance detecting means comprises two light sources for respectively projecting light to two points excluding a point on said locus on said road surface corresponding to two of said three positions of the vehicle and two position detecting means for detecting positions of light reflected from said two points, and said image pick-up means. 
     
     
       9. The apparatus according to claim 1 wherein said road distance detecting means comprises three light sources respectively projecting light to three points on said road surface corresponding to said three positions, and three position detecting means for detecting positions of light reflected from said points. 
     
     
       10. The apparatus according to claim 9 wherein said light sources comprise said laser beam scanning means and laser beam leading means for leading laser beam of a predetermined position from said laser beam scanning means onto said three points. 
     
     
       11. The apparatus according to claim 10 wherein said laser beam leading means comprises a partially transmissive mirror and three lines of optical fiber.